DETERMINATION OF ATMOSPHERIC ALUMINUM BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROPHOTOMETRY UNDER AR+CH4 FLOW

An improvement of sensitivity and reproducibility in the determination of Al by graphite furnace atomic absorption spectrophotometry is desc ribed in this paper. The main problem of Al analysis is here the high temperatures required for the atomization phase, during which refracto ry compounds are formed and the sensitivity decreases. Moreover, furna ce lifetime is shortened and peak heights strongly decrease within a s eries of measurements. An additional flow of methane is tried, in orde r to create a reducing environment and to produce in situ a layer of a tomic carbon and thus to improve furnace lifetime. This method appears to be slightly more sensitive than the use of additional hydrogen flo w, but is far more interesting for furnace lifetime. A set of Al conce ntrations is provided for aerosols as well as for rainwater. This data , established on the basis of a two year sampling at Cap Ferrat (Frenc h Riviera), allows to discuss the behaviour of Al in relation with hea vy metals (Pb, Cd, Cu and Zn) and Saharan dust.